1. Field of the Invention
The present invention relates to organic light emitting display device, and more particularly, to mass production of organic light emitting display devices.
2. Description of the Related Technology
Recently, organic light emitting displays are widely used among organic semiconductor devices and have a simple structure. The organic light emitting displays are self-emission displays in which organic layers are used as emission layers and do not require additional back light in order to emit light unlike liquid crystal displays (LCD). The organic light emitting displays are thin and light. Therefore, recently, the organic light emitting displays are actively developed as display panels of portable information terminals such as portable computers, mobile telephones, and portable game devices, and electronic books.
In a typical organic light emitting display, at least one organic layer including an emission layer is interposed between a pair of electrodes, that is, a first electrode and a second electrode. The first electrode is formed on a substrate and functions as an anode that injects holes. An organic layer is formed on the first electrode. A second electrode that functions as a cathode that injects electrons is formed on the organic layer to face the first electrode.
In such an organic light emitting display, when moisture or oxygen permeates from the outside to an organic light emitting diode (OLED), an electrode material is oxidized and separated so that the life span of the OLED is reduced, that emission efficiency deteriorates, and that emission color changes.
Therefore, in fabricating the organic light emitting display, the OLED is sealed from the outside so that moisture cannot penetrate. In order to seal up the OLED, for example, a polymer such as polyethyleneteraphthlate (PET) is laminated on the cathode of the OLED. Alternatively, a cover or cap is formed of a metal or glass that includes an absorbent. The cover or cap may be filled with a nitrogen gas, and the circumference of the cover or cap may be sealed up by a sealing material such as epoxy.
However, in such a method, it is difficult to make the substrate and the cap tightly attached to each other and to precisely apply the sealing material and thus the OLED is deteriorated and deformed by heat emitting from the OLED.
In order to solve the above problems, a capsule sealing method of improving attachment between the substrate and the cap using a frit as the sealing material has been proposed. In order to commercialize the organic light emitting display using a frit seal, the organic light emitting display is not fabricated using a unit display panel, but is fabricated using a mother substrate unit display panel. That is, after a plurality of display panels are fabricated simultaneously, they are cut or scribed into individual display panel.
When the mother substrate unit display panel using the frit seal is scribed into unit display panels, tension occurs due to heat during a process of annealing or melting the frit. Thus, a scribing crack is irregularly transmitted during the scribing process and the scribing section is formed irregularly. Therefore, the size of the unit display panel varies.